Thales has supplied the French space agency CNES with a Big data processing infrastructure, encompassing hardware and software, for the GAIA mission that is setting out to map a billion stars.

Launched in December last year by the European Space Agency (ESA), the ambitious GAIA galactic surveying satellite is set to revolutionise astrometry as we know it.

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Lancement de Gaia depuis le Centre spatial guyanais de Kourou le 19 décembre 2013

During its planned five-year mission, GAIA will characterise one billion stars with unprecedented positional precision: to within 20 micro-arcseconds for stars of magnitude 15 — equivalent to the thickness of a human hair seen from a distance of 1,000 km. In orbit around the L2 Lagrange point, the GAIA satellite determines the fundamental astrometric and astrophysical parameters of observed stars with its spectro-photometer, spectrometer and astrometry instrument. Each star will be observed approximately 80 times during the course of the mission.

GAIA will thus enable scientists to establish a three-dimensional map of our galaxy and gain further insight into the structure and evolution of the Milky Way. It will also make significant contributions to advancing our understanding of exoplanets, the solar system, outer galaxies and fundamental physics.

The sheer number of stellar observations from GAIA will generate some 50 Gigabytes of data every day, amounting to more than 100 Terabytes of raw data by the end of the mission. After processing, the final data catalogue will be about one Petabyte (1015 bytes). Such huge volumes of data call for a solid data exploitation strategy.

Early in the project, specifications began to grow exponentially as research requirements piled up, multiplying data volumes 30-fold. It soon became clear that conventional data storage technologies would not be up to the task and a different technology more suited to GAIA’s needs had to be sought.

Using a Big data architecture, Thales has supplied CNES with a complete processing system, encompassing hardware and software, geared to the needs of the mission:

  • An estimated one to three Petabytes of data to be stored and processed
  • Scientific processing of tables containing up to 280 billion objects
  • Complex handling of huge volumes of data: joining, filtering and transformation, etc.
  • Complex sequencing and parallel processing, calling for tight orchestration and scheduling


The chief innovation consisted in using Web-based tools (log analysis, text databases) in a science context.

GAIA trains its sights on the galaxy

The GAIA satellite was sent aloft on 19 December 2013 from the Guiana Space Centre in Kourou. A month later, it reached the L2 Lagrange point. This is a very special point in the Sun-Earth system, 1.5 million km from Earth — five times the Earth-Moon distance — and on the far side of the Sun. The L2 point orbits the Sun with the same period as Earth. One year after launch, GAIA has seen the entire galaxy pass in its sights. CNES’s Toulouse Space Centre houses one of the six European processing centres for the GAIA mission, which is scheduled to last five years.


A great success

Brigitte Béhal, Head of the Products and Ground Segments Sub-Directorate at the CNES Toulouse Space Centre (CST): “When we started development, we didn’t know if our technologies would be capable of handling the volume of data required to compile a catalogue of one billion stars, and the data storage issues facing us were immense. The new technologies and databases that Thales proposed enabled us to set up a data processing centre that has proven its reliability and robustness. It really is a great success!